Institutio Oratoria

On the other hand, counsel for the defence must, as far as possible, aim at denying, excusing or extenuating such charges, or, if that be impossible, show that they are not relevant to the case. For there are many charges which not only have no mutual resemblance, but may even at times contradict each other, as for instance if a man accused of theft is called prodigal or careless. For it is not likely that one and the same man should at once despise money and covet it.

If such means of defence are not available, we must take refuge with the plea that the charges made are not relevant to the case, that because a man has committed certain sins, it does not follow that he has committed all, and that the accusers ventured to make such false charges merely because they hoped by injuring and insulting the accused to be able to overwhelm him with the unpopularity thus created.